Hand truck slide assembly



Aug M, 1956 w. E. BOYLAN 2,758,890

HAND TRUCK SLIDE ASSEMBLY Filed Nov. 7, 1952 2 Sheets-Sheet l IN V EN TOR.

WENDELL E. BOYLAN MM rfl ATTYS.

Aug. 14, 1956 Filed Nov. 7, 1952 FIG}. 2

FIG. 3

W. E. BOYLAN HAND TRUCK SLIDE ASSEMBLY 2 Sheets-Sheet 2 WENDELL E. BOYLAN United States Patent H'AND TRUCK SLIDE ASSEMBLY Wendell E. Boylan, Buchanan, MiclL, assignor to Clark Equipment Company, Buchanan, Mich., a corporation of Michigan Application November 7, '1952, "Serial No. 319,403

ZClaims. (Cl. 308-3) My present invention relates generally to powered hand lift trucks and, more specifically, is directed to an improved form of slide assembly for mounting load supporting means to the main frame of a powered hand lift truck.

Presently known powered hand lift trucks. comprise a main frame having a vertical transverse plate member secured to the forward end thereof. Mounted to the transverse plate member for vertical sliding movement relative thereto is load supporting means including forwardly extending horizontal load forks. The forks are adapted to be disposed beneath a pallet supported load after which they may be elevated by means of suitable elevating means. During elevation of the load, the load supporting means moves relative to the transverse plate member and, in order to permit free movement thereof, the interrelated elements of the plate member and load supporting means must be precision machined. This makes for an expensive and complicated slide assembly.

It is a primary object of my present invention to provide an improved form of powered hand lift truck slide assembly wherein precision machining of the interrelated elements of the slide assembly is rendered unnecessary.

It is another object of my present invention to provide a slide assembly of the character indicated wherein proper operation thereof may be effected even though the associated elements of the slide assembly are warped or distorted.

In the preferred embodiment of my present invention the load supporting means is formed with vertical guideways that encompass the vertical cooperating end portions of the transverse vertical plate member forming part of the main frame of the truck. A plurality of small bearing inserts or gibs are mounted in the vertical ends of the plate member and engage the legs and bight portions of the guideways for reducing friction between the plate member and the guideways during relative movement therebetween. As a result of employing the inserts, the ends of the plate member do not have to be machined and may, in fact, even be employed though warped to a slight degree.

It is a feature of my present invention that the bear ing inserts are semi-circular in configuration and are mounted for limited rotary movement in planes extending normal to the transverse plate member. By virtue of this arrangement, the vertical ends of the metal inserts at all times have full surface contact with the adjacent legs of the guideways, while the vertical sides of the metal inserts have contact with the bight portions of the guideways.

It is a further feature of my present invention that the metal inserts are readily replaceable in the event that they should become broken or worn.

Now, in order to acquaint those skilled in the art with the manner of constructing and using the slide assembly of my present invention, I shall describe in connection with the accompanying drawings, a preferred embodiment of my present invention.

In the drawings:

Figure 1 is a perspective view of a powered band lift truck with which the slide assembly of my present invention is embodied;

Figure 2 is a front elevational view of the slide assembly of Figure 1;

Figure 3 is a side elevational view of the slide assembly of Figure 1;

Figure 4 is a plan view of the slide assembly of Figure 1 with portions being broken away and shown in section to illustrate the arrangement of the metal inserts and the guideways;

Figure 5 is a fragmentary sectional view taken substantially on line 5-5 of Figure 4, on an enlarged scale; and

Figure 6 is a fragmentary sectional view, on an enlarged scale, taken substantially on line 6-6 of Figure 4.

Referring now to Figure 1, there is indicated generally by the reference numeral 10 a powered hand lift truck comprising a main frame 12 supported on a rotatable motor-in-wheel power unit 14. Pivotally mounted at its lower end to the motor-in-wheel power unit 14 is a vertically swingable steering handle 16 having suitable controls at the outer end thereof for manipulation by an operator of the truck. Mounted on the top of the frame .12 is a battery case 18 in which batteries are disposed for providing a source of electrical energy for powering the mo-tor-in-wheel unit 14. As is best illustrated in Figure 4, a vertical transverse plate member 20 is secured to the main frame 12 at the forward end thereof. Disposed forwardly of the plate member 20 is load supporting means, indicated generally by the reference numeral 21, which includes a vertical transverse plate member 22 spaced from the plate member 20. The plate member 22 has vertical offset end portions 24 formed integrally therewith. A flange member 26 is secured to each of the offset end portions 24 by means of a plurality of vertically spaced bolts 28. The offset end portions 24 and flanges 26 encompass the ends of the fixed plate member 20 and define guideways having bearing surfaces 30, 32 and 34.

As shown in Figure 3, substantially semi-circular forwardly and rearwardly facing recesses 36 are formed in the ends of the plate member 20. Disposed in the forwardly facing recesses 36 are substantially semi-circular bearing inserts or gibs 38 having vertical forward bearing surfaces which engage the bearing surfaces 34 of the offset end portions 24. The rearwardly facing recesses 36 receive bearing members or gibs 40 having vertical rear bearing surfaces which engage the bearing, surfaces 30 of the flange members 26. The sides of the gibs 38 and 40 frictionally contact the bearing surfaces 32 of the end portions 24. The gibs are free to rotate a limited amount within the recesses 36 in planes extending normal to the plate member 20 and thus full surface contact is at all times maintained between the gibs 38 and 40 and the adjacent bearing surfaces 30 and 34 of the end portions 24. As a result of floatingly mounting the gibs 38 and 40, the ends of the plate members 20 do not have to be precision machined and do not have to be maintained precisely parallel to the bearing surfaces 30 and 34.

As will be understood from what has been said, the movable plate member 22 is provided at each end with a channel, comprising the offset portion 24 and the flange member 26, which receives the adjacent end portion of the plate 20. The gibs 38 and 40 are floatingly mounted in the end portions of plate 20 and project outward slightly beyond the front and back and end surfaces thereof, as shown in Figures 4, 5 and 6, presenting flat bearing surfaces contacting the corresponding interior surfaces of the end channels of plate member 22 and freely alignable therewith. That assures full surface contact between the gibs and the interior surfaces of the channels, with the advantages above noted.

The load supporting means 21 hereinbefore referred to further comprises horizontal forwardly extending load supporting forks 42 which, at their rear ends, are secured to support blocks 44 at the lower forward surface of the movable plate member 22. The load supporting forks 42 are adapted to be inserted beneath a pallet supported load after which they are adapted to be raised by distending the roller members 43 through the actuation of suitable elevating means, not shown. Since the elevating means does not form part of my present invention, it is not believed necessary to illustrate and describe the latter in detail. As the load supporting forks 42 are raised, the plate member 22 moves upwardly relative to the fixed plate member 20 with the end vertical guideways freely sliding along the gibs 38 and 40. Upon lowering of the load supporting forks 42, the plate member 22 moves downwardly relative to the fixed plate member 20 with the end vertical guideways during this movement freely sliding along the gibs 38 and 40.

In the preferred embodiment of my present invention the plate members 20 and 22 and the vertical end guideways may be formed of a relatively hard metal, such as steel, while the bearing inserts or gibs 38 and 40 may be formed of powdered sintered metal, or bronze, or other suitable bearing material. It is to be observed that the gibs 38 and 40 are readily replaceable in the event that they should become broken or worn.

Now, while I have shown and described what I believe to be a preferred embodiment of my present invention, it will be understood that various modifications and rearrangements may be made therein without departing from the spirit and scope of my present invention.

I claim:

1. In a lift truck, a first vertical plate member, a second vertical plate member having channel guideways encompassing the end portions of said first plate member, one of said plate members being movable relative to the other, and approximately semi-circular gibs mounted in said end portions of said first plate member for turning movement and extending outwardly beyond the ends and the sides of said first plate, said gibs having fiat vertical end and side bearing surfaces disposed for bearing contact with the corresponding interior surfaces of said channel guideways.

2. In a lift truck, a first vertical plate member, a second vertical plate member having channel guideways encompassing the end portions of said first plate member, said second plate member being movable relative to said first plate member, the latter having at each side of each end portion thereof a plurality of approximately semicircular recesses of less depth than the thickness of said end portion and opening through the side and the end thereof, and approximately semi-circular gibs mounted in said recesses for turning movement and extending outwardly beyond the ends and the sides of said first plate member, said gibs having flat vertical end and side bearing surfaces disposed for hearing contact with the corresponding interior surfaces of said channel guide ways.

References Cited in the file of this patent UNITED STATES PATENTS 1,059,545 Kunze Apr. 22, 1913 1,699,636 Smith Jan. 22, 1929 1,828,289 Michell Oct. 20, 1931 1,917,621 Weber July 11, 1933 2,045,620 Spullies June 30, 1936 2,455,432 Martin Dec. 7, 1948 2,643,162 Barr June 23, 1953 2,679,437 Pusztay May 25, 1954 FOREIGN PATENTS 547,306 Great Britain Aug. 21. 1942 

